Question

Frog's heart, when taken out of the body, continues to beat for some time.
Select the best option from the following statements.
(a) Frog is a poikilotherm
(b) Frog does not have any coronary circulation
(c) Heart is "myogenic" in nature
(d) Heart is auto-excitable

• A. Only (d)
• B. (a) and (b)
• C. (c) and (d)
• D. Only (c)

Answer 1

The correct option is C (c) and (d)

Myogenic heart contracts by itself without any external nerve stimulus like other muscles in the body. The myogenic heart is excited by a special node called as the sino-atrial node(SA node), a place where the contraction starts. So frog's heart, when taken out of the body, continues to beat for some time. And the statements supporting this are heart is myogenic in nature and heart is auto-excitable.
The frog is a poikilotherm that is the internal temperature varies and frog heart has coronary circulation where the arteries deliver oxygen-rich blood to the myocardium. But both these options do not explain the above statement.